Muhammad ibn Ahmad ibn Yahya narrated, as a mursal report, that it was reported regarding a young girl who dies while in the presence of a man. Imam عليه السلام said: “If she is less than five or six years old, she is buried without being washed.”
Ali Akbar al-Ghaffari
Tahdhīb al-Aḥkām fī Sharḥ al-Muqniʿah, vol. 1, p. 364